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BY JOHN L. LECONTE, ASSISTED BY GEORGE H. HORN.*
The task that I have attempted to perform in the present memoir, is a very difficult one, and I feel that it has been accomplished very imperfectly.
It is, namely, from the study of the very small material represented in the fauna of temperate North America, to induce entomologists to investigate those Coleoptera, which have been heretofore classed as Curculionidae and some allied, but ill-defined families, from a completely new standpoint, whereby they become isolated from all other Coleoptera.
The characters which render necessary this isolation of the Rhynchophora have been already exposed by me in some short memoirs, and their value has been recognized by several systematists of excellent ability, although not to the extent to which I hope the present effort will render them acceptable. These characters are mainly to be found in the form of the basi-lateral elements of the head and prothorax on the under surface of the body, and will be detailed in the Introduction.
By these peculiarities of structure, as well as by their food, the Rhyn. chophora are restricted to a more uniform type of organization than is exhibited in the normal Coleoptera; but at the same time being represented by an immense number of species, the generic modifications are very varied. The difficulty of tabulating these generic forms in a manner to exhibit their relations to each other is therefore greatly increased.
I have previously expressed my opinion that the Rhynchophora, being the lowest type of Coleoptera, are therefore geologically the oldest. Regarding then the fixity of insect types, as shown by the resemblance of ancient forms to those of the present time, the uniformity in food and manner
* See Proceedings, 1875, 619 (Nov. 19th); 662 (Dec. 17th).
of life, and the immense number of genera in this complex, with which we are dealing, we have a right to expect that there will be a proportionally larger survival of unchanged descendants of those species or genera which were first introduced. We will, therefore, have a more perfect series of connecting forms than can be found in other orders of insects, whose methods of life expose them to the influences of destruction or modification by external circumstances.
Nevertheless, the arrangement which I have adopted, will show in the larger groups or tribes, a dominance within the limits of each tribe of one typical modification of structure, with variations in the direction of modi fications which become dominant, and definitive in other tribes.
It thus comes to pass that, neglecting the essential characters of the tribe, to which the species may properly belong, the definition of the genus will approximate in language very closely to that of some other genus, belonging to a very distinct part of the series.
In other words, the genera belonging to several tribes will agree with each other in similar characters of less value than the tribal characters.
What I have just said regarding genera is equally true in respect to species. The form, color and sculpture in many instances are repeated in tribes which from their geographical distribution and method of life cannot be supposed to have any immediate genetic derivation. Instances of this kind of resemblance will be mentioned both in the Introduction, and in the body of the memoir.
I have no theory to propound regarding this very complex system of cross resemblances. They are certainly not the result of mimicry, and probably not of natural selection, or any other name of an idea which has yet been suggested. A deeper insight into the phenomena of organic nature, which may, perhaps, be acquired by our successors would give us a more reasonable explanation of these resemblances. *
My best thanks are due to my excellent collaborator, Dr. G. H. Horn, for his careful study and classification of the ily Otiorhynchida, certainly one of the most difficult among the Rhynchophora, and next to the genuine Curculionide, the largest. I also owe my kindest acknowledgment to Mr. G. W. Belfrage, for a large series of specimens from Texas; to Messrs. H. G. Hubbard and E. A. Schwarz, for very full series from Michigan and Florida; to the Museum of Comparative Zoology of Cambridge for the loan of the Zimmermann collection, mostly from the Southern States ; and to Messrs. E. P. Austin, W. Jülich, and Prof. C. V. Riley for large sets of specimens from various parts of the country. Other friends have
* Mr. A. R. Wallace in his suggestive address to the Biological Section of the British Association for the Advancement of Science, held at Glasgow, 1876, has expressed himself quite clearly concerning the inadequate explanation of the resemblances between objects of diverse genera, tribes and families, which has thus far been offered. He comments at length on a certain relation between color and locality, not dependent on protective tendencies. This, however, is only one of several groups of curious facts which will be developed by more prolonged and minute observation. Vide Nature, Sept. 7th, 1876, p. 101,
also assisted me in proportion to the extent of their respective collections, and to them also I return thanks.
It is only justice to a master spirit in Zoology, who, with more imperfect knowledge of facts than we possess, was endowed with deeper intuition than is usually given to man, that I should conclude this preface with the following quotation from Oken's Physiophilosophy 3526.* What he discerned, I have endeavored to demonstrate.
"I have also declared the Rhynchophora to be the lowest and the Lamellicornes the uppermost in rank. A view, which at present appears to be generally adopted."
Philadelphia, December 23d, 1876. * Elements of Physiophilosophy, by Lorenz Oken, M.D., from the German, by Alfred Tulk, London, Ray Society, 1817. The remainder of the section cited may be read with profit by all students disposed to accept words of advice from one who was well qualified to give instruction; but it is too long to be quoted on the present occasion, though teeming with thoughts suggestive of much that has since been adopted, without due reference to the original source.
Rhynchophorous Coleoptera are those in which the posterior lateral elements of the head* and prothoraxt coalesce on the median line of the under surface of the body, so as to unite by a single suture.
To the first of these characters there is no exception in the wide range of the existing Coleopterous insects; to the second there are two notable discrepancies. The first is Nematidium, commonly classed with the Colydida, the other is the genus Cossyphus, which has been considered as belonging to the Tenebrionida, from the other members of which it differs, not only by the structure of the under surface of the prosternum, but by other characters, which require future study for a proper apprecia. tion of their importance.
I might rest the definition of the Rhynchophora at this point, and proceed to indicate the different series and families into which, according to the system I have developed, these insects should be divided, but before doing so, there appear to me certain relations between the members of this suborder, which are well worthy of attention; and certain characters which I have not had time to investigate fully, but which are indicated for the guidance of those, who will in future adopt the views herein set forth.
There are also certain characters common to all, or nearly all Rhynchophora, most of which I have mentioned in the two essays cited below, but which for convenience may be here briefly recapitulated :
1st. There are no soft, larval, or imperfectly chitinized forms, or forms with short elytra, exposed wings, or greatly multiplied antennal joints, such as are of frequent occurrence among the normal Coleoptera.
2d. There are none in which the side pieces of the prothorax are separated by suture from the pronotum, and very few in which even the lateral margin is indicated; in many the prosternal sutures are distinct, but in some even these are obliterated.
3d. In none are the front coxal cavities open posteriorly, though in some
* Le Conte, American Naturalist, Feb., 1875, ix, 112.
+ Le Conte, American Journal of Science and Arts, July, 1867.
This genus has been recently described by Reitter, Verhandl, naturforsch. Vereines in Brunn, 1876, as belonging to the Trogositidæ, under the name Filumis.
Horn, Tr. Am. Ent. Soc. 1868, p. x.
Am. Journ. Sc. and Arts, July, 1867; American Naturalist, July, 1874.